<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.6.0/jquery.js"></script>
</head>
<body>
    <!-- <button id="open">开灯</button>
    <button id="close">关灯</button> -->
    <button>开灯</button>
    <img src="img/close.png" alt="">
</body>
<script>
    // $('#open').click(function(){
    //     $('img').attr('src','img/open.png')
    // })
    // $('#close').click(function(){
    //     $('img').attr('src','img/close.png')
    // })
    $('button').click(function(){
        var but = $('button').html()
        $('img').attr('src','img/open.png')
        $(this).html('关灯')
        if(but == '关灯'){
            $('img').attr('src','img/close.png')
            $(this).html('开灯')
        }
    })
</script>
</html>